Granular fertilizers are often coated with one or more herbicides before application/use of the granular fertilizers. Herbicides which are applied to granular fertilizers may be highly volatile, include natural or artificial pigment, and/or may not completely adhere to the granular fertilizer. One example of an herbicide often coated on granular fertilizers is pendimethalin. Pendimethalin is yellow in color and has a waxy to oily consistency, especially at temperatures approaching its melting point (˜55° C.). Pendimethalin does not completely adhere to granular fertilizers to which it's applied, in part because of its consistency. Therefore, during handling, granular fertilizers coated with pendimethalin tend to transfer the pendimethalin to other surfaces, e.g. to clothes, skin, and/or application equipment, upon physical contact with the coated granular fertilizers. Residual pendimethalin, which collects on these surfaces, forms a yellow stain or film (comprising pendimethalin) that is very difficult to remove.
Additionally, the transfer of herbicides which are applied to granular fertilizers prior to application is problematic for a number of other reasons. Any transfer of herbicide off of the granular fertilizer is ultimately wasted, i.e., the herbicide does not reach its intended target. Additionally, herbicides which are transferred onto human skin or clothing pose a perceived (or an actual) health risk. Further, herbicides which are transferred onto surfaces of transportation and/or application equipment need to be removed, which leads to down time, cleaning expenses, etc.
Attempts to prevent the transfer of herbicides from granular fertilizers to other surfaces have included encapsulating the granular fertilizers having herbicides disposed thereon. However, conventional methods of encapsulation cause certain herbicides to sublime, melt, and/or vaporize. As such, conventional encapsulation methods are not suitable for certain herbicides, such as pendimethalin. Further, conventional encapsulants may inhibit controlled release of both the granular fertilizer and the herbicide upon application, due to excess encapsulant, inconsistent thickness of the encapsulant, and/or agglomeration of the encapsulated granular fertilizer, which result in waste and added expense. Accordingly, there remains an opportunity to provide improved encapsulated particles and methods of forming such encapsulated particles.